no. 17 measurement • news 2002 · for further information, contact your local agency, or our...

No. 17 MEASUREMENT • NEWS 2002

CONTACTTemperature Measurement & ControlProtective sheaths for pyrometer assemblies

Power Measurement & Control Division

Concentrate your energies!

Test & MeasurementDivision

Three phase qualityanalyser

Innovatingto serve you better

In this issue of your magazine, you will find numerous products andservices that have become available to you over the last few months.For the Test & Measurement division: three phase electrical network

quality analyzer, VAT tester, hand-held multimeter clamps, several megohm-meters, cable tester for LANs and LAN tester. For the Power Measurement& Control division: current transformers, power monitors, new energy metersand a pulse receiver. For the Temperature Measurement & Control division: new temperature measurement applications and as many corres-ponding sensors and associated regulation equipment. Finally, as regardsService, new metrology approvals complete our product offer.

As each year, we are making considerable efforts to provide you with newtools that are totally tailored to your needs, taking your many remarks intoconsideration. Our organization, with its different divisions, enables us toconcentrate and enrich specific skills and technical knowledge, in terms ofmarketing and research and development, for each profession.

In this way, whether they concern electrical safety, user software, ergono-mics and the man-machine infrastructure, cost or long-term quality, thedemands of each trade are better understood and passed on directly byspecialists in the development of new products.

Specialized and dedicated sales teams, in France and for export, are alsoavailable to help you. In each of our divisions, specialized representativescan answer your questions and help you choose equipment that best fulfilsyour specifications.

There are five divisions at your service: Test & Measurement, PowerMeasurement & Control, Temperature Measurement & Control, Service,and Industry.

Do not hesitate to give us a call. We are here to serve you, as we have beenfor almost 110 years, trade by trade.

Axel ArnouxVice-president

Groupe Chauvin Arnoux

2 No.17CONTACTCONTACT

C O N T E N T S E D I T O R I A L

Company information . . . . . . . . . . . . . . . . . . . . . . . .3New ProductsThree Phase Quality Analyzer . . . . . . . . . . . . . . . . . . . .4RMS Multimeter Clamps . . . . . . . . . . . . . . . . . . . . . . . .5Complete certification of LANs . . . . . . . . . . . . . . . . . . .6Wiring checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6Test your surge arresters and insulation resistors . . . . . . . . . . . . . . . . . . . . . . . . .7Special ReportsEarth measurement . . . . . . . . . . . . . . . . . . . . . . . . . . .8Our solutions for your earth measurements . . . . . . .13Metering energy flow . . . . . . . . . . . . . . . . . . . . . . . .16PRISMETER 2 meters on power transmission networks . . . . . . . . . . . . . . . . . . . . . . .17Protective sheaths for pyrometer assemblies . . . . . . . . . . . . . . . . . . . . .18FocusMultifluid remote-readable metering pulse receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14ApplicationsFurnace mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . .21Kiosk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Cover photo:Pyrometer assemblies for high temperatures

PUBLISHING DIRECTORClaude GENTER

MANAGING EDITORAnaïde DER AGOBIAN

EDITOROlivier LOMBAERDE

CONTRIBUTORSAlexandra AUTRICQUERose Marie BERGER

Didier BISAULTSébastien LEFÈVRE

Cécile LE GOUÉPascal PERNIN

Thierry VIGNERONGRAPHIC DESIGN AND LAYOUT

Pastelle CommunicationTel: 33 1 45 45 22 02

TECHNICAL INFORMATION JOURNAL

Communication Dept.190, rue Championnet

75876 PARIS Cedex 18 - FRANCETel: 33 1 44 85 44 85Fax: 33 1 46 27 73 89

http://www.chauvin-arnoux.come-mail: [email protected]

Distributed free all reproduction rights reserved

2002

For further information, contact your local agency,or our export departments in France

TEST & MEASUREMENT DIVISIONTel: 33 1 44 85 44 86 - Fax: 33 1 46 27 95 59 - e-mail: [email protected]

POWER MEASUREMENT & CONTROL DIVISIONTel: 33 1 47 46 78 85 - Fax: 33 1 47 35 01 33 - e-mail: [email protected]

TEMPERATURE MEASUREMENT & CONTROL DIVISIONTel: 33 4 72 14 15 52 - Fax: 33 4 72 14 15 41 - e-mail: [email protected]

CHAUVIN ARNOUX UKTel: 1 628 78 8 888 - Fax: 1 628 628 099

e-mail: [email protected]

To receive sales literature, fill out the Reader Service form between pages 12 and 13.

3No.17 CONTACTCONTACT

C O M P A N Y I N F O R M A T I O N

To better meet professional requirements, the product divisions each havetheir own means for research and development, marketing and sales andare assisted by the group industry division for manufacturing.

Stringent designWhen it comes to developing new products, considerable efforts havebeen deployed to enable the divisions to keep up with the very best andoffer many innovations each year. Compliance with standards, metrolo-gical rigor, ergonomics, technological and marketing watch are key wordsfor our experts in each division. The demands applied in terms of develop-ments are a measure of the quality of the products, designed to last andsafe to use.

Built-in manufacturing Our products are designed in our laboratories in France, Austria or theUSA and then manufactured in our Industry division's factories. Mechanical parts, in plasticor metal, are manufactured in Vire and printedcircuits, in Villedieu. Product assembly andtesting are then carried out in factories inEurope and the USA.

Designing and ManufacturingThe Chauvin Arnoux Group is organized into five divisions: Test & Measurement, Power Measurement & Control, TemperatureMeasurement & Control, Service, and Industry.

Some parts manufactured in the factory in Vire

For improved metrological performancewith compact size at optimized cost,

Chauvin Arnoux integrates ASIC components into its products.

Confirmed quality, Chauvin Arnouxis ISO 9001 certified by TÜV CERT.

Precision mechanics in Vire (Calvados).

An assembly shop in Normandy.

Printed circuit manufacturing in Villedieu (Manche).

EMC laboratory in Pont-L'Evêque for electromagnetic compatibilitytesting on the group’s products.


N E W P R O D U C T

Three Phase Quality Analyzer: check the quality of an electricalnetwork quickly and properlySome days everything goes as planned. However, other days, one failure is followed by another and never comes from the same place or source on the network. It is impossible to get the big picture! In this case, you need Qualistar to check the quality of your network to standard EN 50-160 and detect any polluting equipment!

Random failures, weird operation, inadvertentstoppage, there’s no doubt: you need a power

analyzer. C.A 8332 and C.A 8334 Qualistardevices are designed specially for those who needto check the quality of their network rapidly andobtain a definite result.First, immediately knowing how the instrumentworks is essential. This is why the large brightcolor LCD screen displays the keyboard pictogramswith a particularly well-structured display mode.The keyboard is split into immediately identifiablezones (direct functions, pop-up menus, cursors).

Three separate operations for six display modesThe first operation concerns phenomenonObservation. It is based essentially on graphicrepresentations of the general waveform (mode), for current and voltage. A glance at thephase diagram (or Fresnel diagram) suffices tocheck amplitude, phase shift and the wiring ofcurrent sensors.

At this stage, the user can already highlight thepresence of problems and, if the need arises, cantake analysis further by moving on to the nextstage, Diagnosis.

There are two modes available for diagnosis: the harmonic mode for quantifying and qualifying the influence of harmonics on the voltagestandard across the terminals of each piece ofequipment, on heating of the neutral, or on rotatingmachinery; and the power/energy W mode, whichclearly indicates the various power and energylevels (active, reactive and apparent), but alsogives the power factor value PF, DPF, tangent,information for determining whether there are anypower losses and if it is necessary to installcompensation capacitors, consider a load-shed-ding system, etc. At this stage, we are already thinking in terms of solutions.

Then, the user can move on to the Monitoringstage to check the quality of the network over a period of time he himself defines. Here again,

there are three different modes: recordingduring which parameters are saved; the alarmmode which, with thresholds determined atthe time of configuration, makes it possible to editany overruns occurring during the measurement-taking phase, and finally the transient mode

(C.A 8334 model) displaying and record-ing on three phases, any fast current and voltagephenomena liable to disturb equipment operation.

The “Screen shot” or the immortalized screen!On site, conditions are not always the very bestfor reflecting about, interpreting or analyzing theresults of a measurement run. It may simply benecessary to have need of information to illustratea report or back up expertise. The Screen Shot isa particularly useful application. Simply pressingthe key will immortalize your screen! Later,it will be easy to identify it by its date, time andtype, and call it up to print it or simply display itagain.

In the same way, the software combined with theQualistar devices offers full possibilities ofdisplaying and processing data acquired on site. Its multi-windows and multi-language operationpresents data in the form of graphics, bar chartsor allows its transfer toward office automationtools such as a spreadsheet.

The Qualistar divisions offer many other usefulfeatures. For instance, easy-to-use configuration,on-line help, internal rechargeable battery or thepossibility of direct printout on a printer. All of these are a way of gaining time so as toconcentrate more closely on performing measure-ments. So, for random failures, weird operation orinadvertent stoppages, check your network!

Reader Service No. 1

The Qualistar giant color screen displays clear and detailed results of the various

possible modes. Each feature can be identifiedimmediately on the display and keyboard

for easy test processing operations.


N E W P R O D U C T

F01, F03, F05, F07:Multipurpose RMSMultimeter ClampsChauvin Arnoux has just released a new range of multimeter clamps.They are characterized by a handy size and their exceptional ergonomic design. Completely automatic and RMS, the F01, F03, F05 and F07 offer extraordinary measurement capabilities, making them ideal for electricians.

A host of features accessed with just one handNumerous measurements are available on theirlarge 4,000-count liquid crystal display, dependingon the model: DC and AC voltages up to 600 V/900 V peak, AC and DC current up to 400 A/600 A peak, Temperatures from - 50 to + 1000°C, Resistances up to 40 kΩ, Continuity audible test (with buzzer) and semi-

conductor test (diodes).

Extending well beyond these capabilities, eachclamp offers individual performance making it a tool specifically designed for each user: The “temperature clamp” F03 indicates (like

F07) internal and external temperatures up to1000°C,

The “motor clamp” F05 indicates power, powerfactor, frequency and phase rotation,

F07 benefits from the TRMS AC + DC techno-logy. It also includes the adapter feature,capable of converting it in a jiffy to a tacho-meter, light meter, RH-meter, etc.

There are many more advantages to the range: onF05 and F07, in addition to frequency measure-ment, the inrush current function will analyze thecurrent demands on motor starting. To guaranteefaultless quality, current and voltage measurementis given in true RMS value (RMS) - (TRMS for F07)whatever the current, deform or sinusoidal reading.

This means that the clamps can measure any typeof current, even for applications suffering from thegreatest signal perturbation, like computer powersupplies, fluorescent tubes, etc.

User ease and simplicityMore than simple measuring apparatus, the fourmultimeter clamps offer a host of additional func-tions depending on the models: Open “Hold” display memory for all

the functions,

Automatic AC/DC and range selection, Diode test, Backlighting, Minimum, maximum and peak values, The selectable V-Live function (buzzer warning

of voltage > 45 V peak, considered to be hazardous),

Selectable automatic shut-off, Life and over-range indicators, Date of last calibration.

Maximum safety Naturally, these new clamps are specially design-ed for the industrial environment and offer all thesafety characteristics of their “big sister” versions(grip guard, anti-pinching protection of the aper-ture, accidental overvoltage protection) andconform to the recent demanding internationalsafety standards EN 61010-1 / EN 61010-2-032- 600 V Cat. III pol. 2


The F05 and F07 clamp inrush current functiongives an automatic display of the RMS values

of a sinusoidal signal calculated on , 1, 2 , 5 and 10 signal periods.

Only 193 mm!

Clamping dia. 26 mm• U 1000 R 02 V - 1 x 1852

• H07RNF - 1 x 702

• Bar 20 mm x 5 mm

UAVG MultimeterR

x 1,1

RMS Multimeter

(AC)

RMS Multimeter

(AC+DC)*

Sinusoidal signals with DC component

Distorted AC signals withoutDC component

Distorted AC signals with DC component

Accurate

Errorby defaultcapable ofreaching 30 to 50%

Errorby defaultcapable ofreaching 30 to 50%

Errorby default(depending

on UDCvalue)

AccurateAccurate

AccurateAccurate

Accurate

* For an RMS multimeter (AC + DC), we also refer to TRMS (True RMS).

Why use an RMS multimeter clamp?

12

12

I(A)

I eff(1/2T)

I eff(10 T)

1/2 T T 2 T—2

5 T t (s)


Often referred to as the LAN Tester, the networkanalyzer has to offer high technical perfor-

mance and considerable self-sufficiency in thefield. CERTILAN C.A 7040 stands out at every stepof analysis through its ergonomics and analysiscapability. Comprising two modules - a measurerand a responder - fitted in storage case with a setof essential accessories for network connections,CERTILAN with a frequency measurement rangeof up to 300 MHz, indicates accurately the stateof LAN network conformity, tested according tointernational certification standards TIA/EIA 568through to category 6, ISO 11801 and EN 50173to class E for copper networks.

Simplified parametersThe tests are particularly simple, performed byconnecting the MEASURER: it measures in twodifferent user modes - automatic or manual - for a test run adapted to installer needs. TheRESPONDER, connected to the other end of thelink, handles all the loops needed by measure-ment. Tests are run quickly and correspond to

the specific properties of multi-pair or coaxial transmission lines used in computer transmissionnetworks: Next (Near-end crosstalk), Elfext (Far-end crosstalk), attenuation, ACR, Return loss(matching), Skew (propagation time difference),line length, loop resistance, mapping (cabling) andfault location up to 30 m distance. The apparatuschecks continuity and measures optical fibre attenuation in mono-mode and multi-mode. Finally,it detects automatically the unwanted voltages onthe line that would interfere with measurements.

Self-contained memoryThanks to the extraordinary memory capacity ofthe MEASURER which stores the results, up to1,700 complete tests can be filed away. What ismore, this number of certification results isunchanged in category 6! It is even possible tosave curves. Offering outstanding ergonomics withnavigation and selection keys, CERTILAN alsooffers users different languages for their menus(French, English, German, Italian or Spanish). The graphic liquid crystal screen is backlit

to guarantee optimum legibility. The intercom function which is built into each module allowstechnicians to communicate from both sides ofthe network while taking remote measurements.

Transfer and printing in a jiffyTest efficiency is complemented by the quality of the issued certification reports. CERTILANcomes with its certification software on the PC:CERTISOFT, a way of importing results of testsstored by the meter in a few simple clicks. Thereare two operating modes: “certification” or“graphic”, subsequently proposed for processingthe results in the Windows™ environment, depend-ing on the desired mode.


N E W P R O D U C T

Complete certification of LANs in just a few steps After installation, any copper or optical (computer or telephone) local area network must be certified to highly specific procedures. The new CERTILAN C.A 7040 networkanalyzer measures the performance of your LAN to ensure its conformity with current andfuture international standards. It is light and handy, immediately adopted for extremely completeand reliable certification jobs.

The tester consists of two modules, the testeritself and a receiver. This equipment will locally

test any cable before installation by looping itback directly to the tester. The use of the remotereceiver mode also allows remote testing of cablesalready installed in baseboards or wiring cabinets.

In a jiffy, the tester will verify any continuity faultaffecting Ethernet networks (10BaseT, Ethernet10 Base2, RJ45/RJ11, 258A, TIA-568/A568B)or Token Ring by detecting cutoffs, short-circuits,cross-wiring and by earth testing.Several additional features have been added tothe basic functions to improve user capability.Above all, the user can choose to run the test intwo different modes:

automatic, pressing the Test key will immedi-ately trigger a scan, LED by LED, along eachof the rows corresponding respectively to thetransmitted signal and the received signal;

in manual mode, the same operation takesplace at the rate set by the user, generating awire-by-wire test.

The detection of any break is reported by a buzzer,in which case the test is stopped and can then beresumed using another key.Before or after cable installation, the C.A 7010simply ensures cabling conformity at the lowestcost.


Wiring checks as simple as that A pioneer within Chauvin Arnoux’s LAN and telecommunications testing range, the C.A 7010 cable tester is stunning in its simplicity, ease in handling, and price. It takes just a few seconds to check the conformity of multipair or coaxial cables.


N E W P R O D U C T

Lightning arrester testsA lightning (or para-overvoltage) arrester is a deviceproviding protection against perturbations ofatmospheric origin.

The role:To limit transient overvoltages from networks toan acceptable level for the electrical equipmentof an installation. So as not to endanger electricalequipment, it is necessary to check that thesearresters work to prevent lightning-induced over-voltages. To avoid problems with difficult test condi-tions, MX 604 has been given an ergonomiccapacity making it an easy task to quickly testpara-voltage arresters, whether dismounted on insitu.

Two possible methods Tests on removed lightning arresters:

A lighting arrester support module is connectedto the head of the unit. The user simply insertsthe lightning arrester to be checked (260 V or420 V lightning arrester) in the appropriatehousing, depending on its shape and pressesthe test button on the support module. Thedeviation of the pointer on the MX 604 dialindicates the imposed voltage limit value setby the lightning arrester.

In-situ lightning arrester tests:A support clamp that can be adapted to a remote control probe is a way of testing light-ning arresters in place, without disassembly,by pressing a test button on the probe.

Application example: telecom installations MX 604 is designed for testing lightning arrestersand insulation during malfunction checks on opera-tional telecom lines. Its functions have been designed in close collaboration with FranceTelecom.

On telecom lines, lightning arresters are generallyat the telephone exchange, in the distributionframe, but may also be located at the distributionsub-frames.

The test procedure consists in applying a 0 to 600 V DC voltage gradient and checking that

the lightning arrester limits the voltage in its speci-fied range.

What result is needed to ensure that overvoltagelimitation characteristics are not drifting?

Whether using the disassembled lightning arrestertest module or the clamp for testing in situ, the valuegiven on the dial shall be included between:• 220 and 430 V for 260 V lightning arresters• 330 and 650 V for 420 V lightning arresters

Insulation testsWhen it is not equipped with the lightning arrestersupport clamp, the remote control probe can beused for testing insulation resistors. On a loga-rithm scale, the results of the measurement canbe read directly without changing calibres.

For better safety and precision in measurement, avoltage presence indicator light warns the user ifthe installation is still live. This situation is counterto the requirements of the insulation test.

An application example:Insulation between a telephone pair and a screenconnected to earth.

Check there are no AC or DC voltages between a pair and earth.

Measure the insulation between each conductorand earth (Ra then Rb) at 50 V on cables in operation:Ra = Rb (+/- 20%) and R > 50 MΩ to 100 MΩ

MX 604:A few characteristics

IEC 1010-1 Cat. III conformity for 300 V

A casing adapted to use in the field: anti-shock,elastomer and resistant to the harshest environ-ments.

Direct analogue and clear reading without changing calibres in all functions:- insulation reading scale- lightning arrester limit voltage reading scale.

An AC voltage presence LED to check de-energizing before insulation tests.

A function rotary selector (6 functions):- “lightning arrester test” position- “battery test” position - 3 “insulation test” positions: 50 V, 100 V and500 V.

Supplied complete, MX 604 is delivered readyto use.

The equipment and its accessories (lightningarrester support, remote control probe, testprobes) are delivered in their own case.


Test your surge arresters andinsulation resistors in telecominstallations Specially designed for the telecommunications market, MX 604 is a lightning arrester (or para-overvoltage) tester, also capable of testing insulation resistance.

Test Characteristicfunctions

Lightning arrester test

Test voltage Gradient 0…600 VDC

Class 2.5

Short-circuit<400 µAcurrent

Insulation test

Test voltage 50 V, 100 V and 500 VDC

Measurement range 100 kΩ…20 MΩ,200 MΩ and 2000 MΩ

Class 10

Battery test

> 200 mA

Ra Rb

x pairs of subscribers

1

2

3ab

Telephoneexchange

Telephone cable

To subscriberbox


S P E C I A L R E P O R T

Earth measurement The extraordinary explosion in the use of electricity in everyday life,private and professional, and the extraordinary development of the distribution networks that followed meant rewriting the professionalpractice rules for installation construction. Standard NF C 15-100 stipulates the general installation conditions to be fulfilled to ensure the safety of people, pets or farm animals, and the protection of property from danger and damage that could becaused by the use of electrical installations.

However, there is no guarantee that the safety measures implemented willbe efficient unless regular tests confirm their performance figures.

Risks due to a lack of protection of electrical installations can represent:- a real danger to human life,- the imperiling of electrical installations and property.

For the user, anybody coming into contact with electric voltage, depending onthe power involved, will suffer more or less serious effects, sometimes fatal.The results of studies by a working group consisting of doctors and experts insafety have determined a permanent contact voltage accepted as not beingdangerous to individuals: 50 V AC for dry rooms, 25 V AC for wet rooms and12 V AC for immersed rooms.

Connecting an earth electrode Why have an earth electrode?The legislation, with a concern for safety, has made an earth electrode instal-lation mandatory. It avoids dangerous increases in earth potential and theaccidental energizing of metal or conducting earths that an individual maytouch. When an abnormal (or fault) voltage is generated, the outflow of theassociated “fault current” through the earth connection will trip protectiondevices if necessary. Therefore, an earth connection must always be associated with a cutoff orwill be otherwise of little interest.

Which earth resistance value needs to be established?In an installation built to standards, to guarantee individual safety, protectiondevices must trip as soon as “error voltage” circulating through the instal-lation exceeds the limit voltage accepted by the human body. To minimize risks, we will consider: U limit = 25 V AC

In addition, in general in domestic installations, a differential cutoff device(VCD) associated with the earth connection, will accept a current increasesof 500 mA.Through Ohm’s Law, U = RIWe obtain: R = 25 V / 0.5 A = 50 Ω

To guarantee the safety of people and property, the earth electrode resistance must be less than 50 Ω: R earth < 50 Ω

Setting up of an earth connection A good earth connection (i.e. with resistance < 50 Ω) depends on threeessential elements: - the nature of the earth connection,- the nature and resistivity of the soil,- the earth conductor.

Nature of earth connectionsIn conformity with standard NF C 15-100, earth connections can be any oneof the following types:- vertical metal rods or tubes- horizontally laid buried cables or tapes- metal plates- metal belts running at the bottom of ditches- reinforcement metal in concrete embedded in the earth- metal water distribution pipes (with agreement of water distributor)- etc.

The resistance of the earth electrode obtained in this way will depend onits shape, its location in the earth, and therefore the resistivity of the soil.

Concept of earth resistivity The resistivity (ρ) of the earth is expressedin Ohm.meter (Ω.m).This corresponds to the theoretical resis-tance in Ohms of an earth cylinder havinga section of 1 m2 and a length of 1 m.Resistivity varies considerably dependingon areas and type of soils, depending onthe humidity and temperature factors (frostor drought increases it).

For example:

1m R=

1m2

Type of earth Resistivity (in Ω.m)

Marshland from a few units to 30

Clayey soil 20 to 100

Humus 10 to 150

Jurassic marls 30 to 40

Clayey sand 50 to 500

Silica sand 200 to 3000

Bare stony soil 1,500 to 3,000

Stony soil overlaid with lawn 300 to 500

Soft limestone 100 to 300

Fissured limestone 500 to 1,000

Mica schists 800

Altered granites and clay 1,500 to 10,000

Highly altered granites and clay 100 to 600



Why measure soil resistivity? - to choose, whenever possible, the location and shape of earth electrodesand earth networks before they are built,

- to provide for electrical characteristics of earth electrodes and earth networks,- to optimization the construction costs of earth electrodes and earth networks(gain in time to obtain the desired earth resistance).

When should resistivity be measured?- on land under construction,- for extensive tertiary buildings (or energy distribution substations) for whichit is important to choose accurately the best earth electrode location.

Various methods can be used, but that most widely employed to determinesoil resistivity is the WENNER “four electrodes” method.

Measurement principle:Four electrodes are placed in line on the earth at intervals having a length a;Between the two end electrodes (E and H), measurement current I is injectedby a generator. Between the two central electrodes (S and ES), the potential ∆V is measuredwith voltmeter.

Note: the terms X, XV, Y and Z correspond to the name formerly used respec-tively for electrodes E, Es, S and H.

The measuring equipment used is a conventional earth Ohmmeter capableof injecting current and measuring ∆V. The resistance value R read on the ohmmeter will allow the resistivity to becalculated by the following simplified calculation formula: ρ = 2π a R With ρ: resistivity in Ω.m at the point 0 or at a depth h = 3a/4

a: measurement base in mR: value (in Ω) of resistance read on earth ohmmeter.

EDF recommends measurement with a = 4 m minimum.

Resistance measurement of an existing earth electrodeAt present, we have a configuration in which the earth electrode alreadyexists and for which we want to check that it corresponds correctly to safety standards. Therefore we want to check that:R earth < 50 Ω.

There are several methods that can be applied depending on the instal-lation configuration.

Which method do we use?

Earth measurement principleE is the earth electrode to be measured

Using an appropriate generator G, AC current (i) at a constant level is madeto circulate through auxiliary connector H referred to as the current injectionconnector with return via an earth connector E.Voltage V is measured between connections E and the point in the earthwhere the potential is zero, using another auxiliary connector S referred toas the “0 V potential connection”. The voltage quotient V measured in thisway by the injected constant current (i) gives the desired resistance.RE = UES/IEH

Important note:The fault current flow is first through the earth electrode contact resistors.The further the distance of the earth electrode, the more the resistancenumber of the parallel contact will move toward infinity and establish analmost zero equivalent resistance.

3a

a a aV

h = 3/4 a

a/2

E(X) ES(Xv) S(Y) H(Z)

G

I circulating through earth

VEarthelectrode

to be measured

E(X) S(Y)

OV

H(Z)

G

Area of influence E

Area of influence H

U = O V

E H

Method Building in countryside Building in urban setting Multipleaccording to with possibilities of without possibility of parallel earthconfiguration sinking rods sinking rods networks

62% method

Triangle method

62% variant method

PE phase loop measurement

Earth clamp

HEArea of influence E

Area of influence H

Top view



From this limit, whatever the fault current, potential will be zero.Therefore, around each earth electrode through which current conducts, thereis an area of influence whose shape and extent are not known.During measurements, every endeavor will be made to set an auxiliaryconnector, referred to as the zero V potential connector, outside theinfluence areas of the auxiliary connectors through which the currentconducts (i).

Various measurement methodsLine measurements method referred to as “62%” (two rods)This method requires the use of two auxiliary electrodes (or rods) for currentinjection and for 0 V potential reference. The position of the two auxiliaryelectrodes compared to the earth connection to be measured E(X) is of particular importance.For the measurement to be accurate, the potential reference auxiliaryconnector(s) must not be installed within areas of influence of earth E andH created by the circulation of current (i).Field statistics have revealed that the ideal method of guaranteeing thehighest measurement precision consists in placing rod S at 62% of E onstraight line EH.Then, we ensure that the measurement varies little by moving rod S by ± 10% (S’ and S”) either side of its initial position, always on straight line EH.If the measurement varies, it means that (S) is in an area of influence andthe distances will have to be increased and measurements started over.For the measurement obtained to be correct, rod H for the earth electrodeto be measured must be at least 25 meters away.

The triangular measurement method (two rods)This method also requires the use of two auxiliary electrodes (or rods) and is used when the previously described method is impossible to use (becausethe alignment cannot be obtained or an obstacle prevents sufficient distancefrom H).Further, it should not be considered as a reference method because it is lessaccurate than that of the “62%” method:

- earth electrode E and rods S and H form an equilateral triangle (when possible)- make the first measurement by placing S on one side and a second placingS on the other.

If the values obtained differ considerably, rod S is in an area of influence, inwhich case it will be necessary to increase the distances and start themeasurements again.If the values found are similar to within several %, the measurements can beconsidered correct.

However, this method gives uncertain results. Even when the values foundare similar, it means that the areas of influence may be overlapping.To check, start the measurements again and increase the distances.

62% alternative method (one rod)(using a TT or a loaded IT scheme only)This method does not require the disconnection of the earth bar, and only callsfor a single auxiliary rod (S).Here, the rod H consists of the earth of a distribution transformer, and rodE consists of the PE conductor accessed on the protection conductor (orearth bar).

The measurement principle is the same as for the 62% method: rod S will bepositioned in such a way that the distance S-E equals 62% of the overall distance

Earthbar

Potentialcompared to S

E S' S S" H

0 Vb ca

V

0 52% 62% 72% 100%

Disconnect the earth bar before measuring

Area of influence

Area of influence

Earthelectrode

to measureE(X)

H(Z)

S(Y) (1st measurement)

S(Y) (2nd measurement)

Disconnect the earth bar before measuring

PE

H S

100% 62% 0

E

321N

DDR

Fuses /Circuit-breaker

Rtransformer Rearth



(between E and H). Therefore, S will be located normally in the neutral “O V reference earth” area.The measured voltage divided by the injected current gives the earth resistance.The differences with the 62% method are:- The measurement supply is from the network and no longer from batteries or cells.- A single auxiliary rod is needed (S rod) making it faster to prepare the measu-rement.

- There is no need to disconnect the building earth bar. This represents a gainin time and guarantees maintained installation safety during measurement.

Phase-PE loop measurement (TT scheme only)In town, the earth resistance measurement is often difficult when the auxili-ary rod method is used because there is no way of setting up rods becauseof a lack of space, concrete surfaces, etc.In this case, in the urban environment, loop measurement does not requirethe installation of a rod and connection is simply to the power supply network(mains connector).The loop resistance measured in this way also includes the earth to bemeasured, the earth and the internal resistance of the transformer and thatof the cables. All these resistances are very low, and the measured value isan earth resistance value by excess.

The real earth value is therefore less than: R measured > R earthThe measurement error (by excess) induced by this method is likely to improvesafety.Standard NF C 15-100 considers that the loop resistance value (earth resis-tance by excess) can be taken into consideration instead of the earth resis-tance, to satisfy rules concerning protection against the risks of indirectcontact.

Note: For a TN or IT (loaded) scheme, loop impedance measurement willallow short-circuit current calculation and therefore, the correct sizing of theprotection devices.

Earth clamp measurement Some electrical installations have multiple parallel earth connections, inparallel in some countries in the world where earth is “distributed” to eachuser by the energy supplier. In buildings with sensitive electronic equipment, a grid of earth conductorsleading to multiple earth electrodes will obtain an earth plan without anyequipotential defect.

For this type of network, speed and safety of the testing processes can beoptimized by an earth connection. In this case, there is no need to isolate theinstallation (by opening the earth bar) or to sink rods.Simply clamping the cable on the earth electrode will give an indication of theearth value and the current circulating through that point.An earth clamp consists of two windings: a generator winding and a receiverwinding.

The “generator” winding of the clamp develops alternating voltage at aconstant

level E around the enclosed conductor; current I = E / R loop then circulatesthrough the resistive loop.

The “receiver” winding measures this current. When E and I are known, the loop resistance can be worked out.This is the case of a parallel earth network. Considering that “n” resistorsin parallel are equivalent to a resistance Raux of a negligible value, we canmeasure the local earth value Rx:

R loop = Rx + Raux (where Raux = resistance equivalent To R1 ... Rn in parallel)

Since Rx >> Raux, we obtain R loop # RX

The earth clamp is used for earth resistance measurements:- on MV/LV transformers,- on buildings with Faraday cages- on telecommunications lines- and for “underground earth” loop continuity.

i

I

Amplifier i

Voltagegenerator

E eNg

Nr

RxRz

Earth electrodeto be measured

R1 R2 Rn-1 Rn

PE

321N

DDR

Fuses /Circuit-breaker

Rtransformer Rearth


Coupling measurement Strong coupling between two earths can have disturbing consequences regard-ing personal and/or equipment safety.The outflow of fault current via the earth M of an MV network can cause theearth potential to rise, and therefore the neutral earth of the LV network,endangering the lives of people and the equipment using LV networks.If lightning strikes an MV/LV transformer, the instant potential increase canamount to several kV.The method to be used is that of in-line measurement referred to as the“62%” method.The setting out of the auxiliary rods H (current return) and S (potential reference) shall be chosen in such a way as to ensure:- that coupling does not occur with the earth electrode to be measured whilecomplying with the distances indicated in the following diagram,

- the earth potential reference validity.

The coupling measurement is made as follows:1) - Disconnect the Neutral from the LV network (open A)*

- Connect E and ES to N (LV neutral earth) using two 50 m cables- Connect S to the first rod with a 50 m cable- Connect H to the second rod with a 100 m cable- Place the meter between M and N at 20 m from their center line- Make the neutral earth connection resistance measurement: R neutral (* the opening of point A will be necessary to allow coupling measurement of the first

neutral earth connector)

2) - As above but with E and ES connected to M (MV network earth connection)(the LV neutral is still disconnected)

- Make the earth electrode resistance measurement: RGrounds3) - Connect E and ES to M (MV earth connection) using two 50 m cables

- Connect S and H to N Earth or LV Neutral) using two 50 m cables- Make the RGrounds/Neutral measurement

4) - Calculate the coupling: R Coupling = [R Earths + R Neutral - R Earths/Neutral] /2

5) - Calculate the coupling factor: k = R coupling/R Earths- This coefficient must be < 0.15 (EDF directive)

Important: remember to connect A back again


MV Network

LV Network Phase

Neutral

M N

MV Network

LV Network

Phase

Neutral

A

M N

E ES S

S

H

H

50 m

20 m

50 m

50 m

100 m 50 m

1

MV Network

LV Network

Phase

Neutral

A

M N

E ES S

S

H

H

50 m

20 m

50 m

50 m

50 m

100 m 50 m

2

50 m

MV Network

LV Network

Phase

Neutral

A

M N

E ES S

S

H

H

50 m50 m

20 m

50 m

50 m

50 m

50 m

3

Coupling measurement method

1

2

3




Our solutions for your earth measurementsDepending on the configuration of the installation to be tested (urban area, possibility of sinking rods, earthnetwork), you will probably prefer one measurement method to another.

C.A 6421/6423/6425Stand-alone and reliable (measurement validation by self-diagnosis), theearth testers (C.A. 64521/6423) and resistivity/coupling testers (C.A 6425)were designed for use in the field: sealed site-adapted casing and display legibility. Analogue (C.A 6421) or digital, they make it possible to makemeasurements using traditional rod methods.Measurement range:C.A. 6421: from 0.5 to 1,000 Ω (log scale)C.A. 6423/6425: from 0.00 to 2,000 Ω (3 automatic ranges)


TERCA 2EDF-approved, TERCA 2 is a reference for measuring earth,respectively and coupling infor-mation under difficult conditions(spurious voltages, high telluriccurrent, etc.). The tester offersmany advantages such as testcurrent selection, direct readingof measurement on large displayand automatic testing of measure-ment conditions.Equipment range:2 Ω to 20 kΩ (5 ranges)Rechargeable built-in battery using internal charger.


C.A 6115NWith the possibility of 14different measurements (in-sulation, continuity, phaserotation, RCD), this installa-tion tester is the mostcomplete in its generation.In particular, it is capable ofearth measurements usingthe 62% alternative method(single rod) or loop measure-ments, without causing thedifferentials to cut out.“Single rod measurement” range: from 0.15 Ω to 10 kΩ“Loop” range: from 0.08 Ω to 200 Ω (resistance and impedance)Built-in battery rechargeable by internal charger.Memory capacity 800 measurements.

C.A 6410/6412/6415: Earth clamps

For a multiple parallel earth networkforming several successive loops, earthclamps offer the advantage of fast earthtesting safely by simple clamping.C.A 6412 and 6415 also allow the measurement of leakage current flowing into the earth.C.A 6415 also offers an alarm function (if a threshold is exceeded) and arecording function (memory capacity 99 measurements). “Resistances” range: from 0.10 Ω to 1200 Ω“RMS current” range: from 1 mA to 30.00 ABatteries or rechargeable cells.


EARTH MEASUREMENTResistivity 62% method 62% L-PE loop

Coupling Measurement Triangle alternative measurement

measurementmethod

C.A 6421C.A 6423

C.A 6425 TERCA 2

C.A 6115N

Chauvin Arnoux offers a full range of products to meet your needs and demands.



Enerdis has been developing, manufacturingand marketing energy management systems

and supervision apparatus for more than ten years.CCT draws on this experience in the areas ofmeasurement, testing and metering of electricity.

This product gathers and stores, in real time,pulses from various energy meters (electricity,water, gas, thermal energy, compressed air, etc.) ordigital signals (circuit-breaker state, alarm tripping,door opening), transmitting them via its RS 485digital output toward a supervision system (withthe possibility of using the WinThor supervisionand energy management software). The type ofmeter unit m3, m3/h, kWh, MWh) is programmable.

With CCT, meters communicateControlling and optimizing energy consumptionmeans regularly monitoring a great number ofmeters. Using CCT, any meter with a pulse trans-mitter, whether electromechanical or electronic,can be read automatically, reliably and quickly.With eight pulse inputs and its RS 485Modbus/Jbus digital output, CCT keeps constanttrack over long distances of the changing meterindexes. This remote reading also enables usersto improve efficiency while devoting more time tothe investigation and optimization of theirconsumption.

Using pulses supplied by the meters, the CCT canmemorize, for each of the inputs, the last twelvemonthly meter indexes and the general meterindex. It also records real time values making itpossible to re-establish the load curves. 4,032mean values can be memorized for each of itseight inputs over a time programmable from 1 to60 minutes (i.e. 28 days self-sufficiency for 10minutes integration or 168 days for 60 minutesintegration) and synchronized on internal orexternal pulses.

Queried via its RS 485 Modbus/Jbus digital outputat a distance, CCT restores consumption figures,giving users far more pertinent information thana simple index reading.

CCT completes the range of ULYS electronic metersEnerdis has re-established its position as the mainplayer on the modular meter market with the recentlaunch of its ULYS electronic meter range. Singleor three-phase, single or double tariff, with activeand reactive energy metering, all these metershave a pulse output. Combined with these metersand the WinThor energy monitoring and manage-ment software, CCT offers users a global andcomplete solution for monitoring and managingall their meter points.

CCT, a real surveillance agentEach of the eight inputs of the CCT can beprogrammed (via SESAME) as an digital signalmonitoring input. When a change of state occursat an input, CCT memorizes the date and time ofthe beginning and end of the event (circuit-breakerstate, alarm tripping subscribed power overrun,tariff changeover, process start, door opening). Itmemorizes the last 50 changes of state for eachof its eight inputs.

CCT, a universal toolIn addition to the fact that this single device allowsanalysis of meter signals and memorizes majorevents, it is totally adapted to user requirements.Using our SESAME configuration software, eachinput can be programmed for every possible typeof unit (m3, m3/h, kWh, MWh), pulse weight,communication parameters (address, speed,parity). The user can also choose the initializationvalues of the metering indexes.

CCT comes with an RS 485 two-wire Modbus/Jbusdigital output. This communication protocol is recognized by all the leaders in the world ofindustry and logic control, offering easy and rapidintegration of CCT into any supervision system onthe market.

Regulatory meter synchronizationFor particularly precise consumption analyses, itbecomes necessary in some cases to synchro-nize load curve power demand calculations (more

often referred to as the top 10 min) with the regu-latory meter point. CCT is programmed to select,for each input, a synchronization by an externalsignal or by a CCT internal clock.

A 24 V DC integrated power supplyOn CCT, there are two terminals providing accessto the 24 V DC power supply used for activatingsignals from the meter pulse transmitters.

CCT and WinThorA specific driver has been developed to operateand utilize every possibility of the CCT for ourWinThor monitoring and energy management software.


F O C U S

Concentrate your energies!CCT is a Multifluid Remote-readable Metering Pulse Receiver,the latest of the Enerdis communicating products for energymetering and management. Its eight pulse inputs, its considerable memorization capacity and its universal digitaloutput, combined with a compact design and simple operation make it the highest performance tool on the market for the remote operation of a pulsemeter or the monitoring of digital signals.

15No.17 CONTACTCONTACT 15

F O C U S

Example of electrical network monitoring and energy management

Field bus

JBusTM/RS485

R&D department

Testing department

Production Administrative Building

CCTPulsereceiver

CCT Pulsereceiver

General WATERmeter

General GASmeter

PRISMETERelectronic tariff meter

ULYS ULYS ULYS ULYS

actif

réactif

Main powersupply

Electrical network

Pulse


Metering energy flow within thecontext of deregulationThe recent deregulation of the energy market has lead to the creation of, among other things, a new player:electric transmission network management. This latter guarantees the continuity and the quality of public utilities made available to its new customers - producers on one side and consumers and distributionsystems on the other. To complete its mission, this management must be able to access certain productionand consumption information. Thus electric transmission network equipment needs to evolve so that the flowof electricity that transits this network can be metered.

New needs in electric transmission network metering

In 1996, the European Commission adopted a guideline which opened theelectricity market to competition: European consumers will be able to even-tually chose their own electricity supplier. As a requirement for opening the energy market, electricity transmission hadto be separated from its production by creating independent entities. A singleelectric utility management for the transmission of electricity is required ineach country. This management is to be in charge of high and very highvoltage lines (63kV to 400kV), all those that connect electric power plants,eligible industrial sites, electric networks, its new customers, and electricalnetworks in neighboring countries. Thus our management's role is to invoice the cost of transmission to thesenew users, establish the variance between production and consumption fore-casts and realizations, and set up their settlement.Running an electric transmission system means ensuring, in real time, thebalance between the consumers demand for electricity and the suppliers’supply. To ensure this balance, the network management needs to be able

to do as needed with the energy reserves, using them as they rise or fall inrelation to the direction of total imbalance noted. Even if the global balancebetween production and consumption can be maintained, this doesn’t neces-sarily mean that the same production-consumption balance holds true foreach of the suppliers. Thus detailed accounts need to be established aposteriori to identify the differences between the production-consumptionresults of each producer and then follow through with their financial regularization.Furthermore, the network management ensuring the functioning of the electric transmission network needs to be paid for this service.

Metering improvements

Input and output points for a metering-equipped transmission system In order to calculate and regulate variance in the product-consumption resultson the one hand and transmission service invoice on the other, it is neces-sary to know the energy flow that transit the electrical transmission network.This is the reason why all production and consumption points connected to

Electric transmission system equipped with metering

Nuclearpower plant

RegionalDispatching

Load curveproduction

Industrialcustomer

ELIGIBLECUSTOMER

Residentialcustomer

MV distributionlines (20 kV)

HV and VHV lines (63 to 400 kV)

Wind turbines

PRODUCTION

Sourcesubstation

PRISMETER 2P

PRISMETER 2P

PRISMETER 2P

PRISMETER 2P

STN

STN STN

STN

TRANSMISSIONDISTRIBUTION



an electric transmission utility need to be equipped with a remote-meteringsystem. This remote-metering system requires 2 meters on each meteringpoint to guarantee data metering without interruption. On top of this, if one can choose one’s supplier, this means that, in theclient's metering structure, energy measurement must be separate frommetering system installed by the energy supplier. The part that measuresmust be physically separate from the part that fixes the price.

Sophisticated metering systemsAmong the elements of this system, remote servers, modified to activelyand dynamically manage the double-meter system, have been installed in theseven regional dispatchings. Data collected at this level is then transmitted to a server center wherevariance is calculated. Other elements in the system, energy meters are installed in all of the trans-mission network’s input and output points; they communicate data to theservers. Because they have an integrated communications port, programmingand maintenance can be carried out on site.

Doted with features such as billing and real-time monitoring, these toolsare highly robust (notably in electromagnetic environments) and reliable(with a very low failure rate). Because large amounts of energy are being billed between different compa-nies, it is important for the meters to be extremely precise. It is for thisreason that transmission network metering is structured around fourquadrants (import-export energy) which measure active energy with an accu-racy class of 0.2S and reactive energy with class 2.

The meters are equipped with a switched telephone network (STN) modemso that the return of data can be carried out at a distance. Since as soonas they are placed in operation on their designated telephone line, thesemeters are linked up and accessible no matter their location. Using radio-type clocks, local synchronization for these meters providesynchronized average powers which can be called upon and thus can recons-truct production and consumption load curves.


Accuracy The PRISMETER 2 meter is especially adapted for HV and VHV energy flow(energy production, interconnection, etc.). Because of its high metrologicalaccuracy, it is destined for metering large quantities of energy. Reminder: itmeasures active energy with an accuracy class of 0.2S as per IEC 687 andreactive energy with class 2 as per IEC 1268.

4 quadrants / load curveThe meter measures and records energy transiting in both directions (produc-tion / consumption). There are 6 energy indexes: active energy produced andactive energy consumed, reactive energy produced and reactive energyconsumed for which there is also inductive reactive energy and capacitivereactive energy. It records load curves (average power demands) over aprogrammable integration period of 1 to 60 minutes.

Time synchronizationEquipped with its own time-stamping clock for dating constituent elementsof the load curve, the PRISMETER 2 is also fit with an input for synchroni-

zing with an external signal. Synchronization with an accuracy

inferior to 100ms of the readload curve is carried out byconnecting the installed metersto a time central receivingeither radio or GPS satellite.

Remote-readingA communicating meter, the PRISMETER 2 is equipped with a STN modem.In this way, metering points from the entire production (connected to a trans-mission system) are repatriated to regional dispatching servers remotelyvia a telephone line. This data is made available to customers (distributorsand eligible industrials). It also has a Teleinfo digital output (2 wire bus) sothat end customers carry out their own energy management.

Power qualityThe PRISMETER 2 meter also provides optional qualimetry features, notablycontinuity measurement and recording (interruptions, voltage dips andsurges, frequency, slow variations in voltage), and the supply’s quality (currentand voltage harmonics measurement up to the 40th order, unbalance measu-rement).

PRISMETER 2 has also been improved. In the event that a STN telephoneline can not be installed, it is possible to connect it to an external GSMmodem.PRISMETER 2 is equipped with pulse transmitter outputs. The weight of thelength of the 4 pulse outputs are programmable, which means that the clientcan adapt his system to suit his needs.



The PRISMETER 2 meter comes in two mechanical formats:the 1/2 19” rack-mountable version for electrical cabinets and

the surface-mounted version for metering panels.

The PRISMETER 2 meter alsocomes with or without an auxiliary

power supply, class 0.5S or 0.2S.

PRISMETER 2 meters on powertransmission networksIn France, the PRISMETER 2 meter was chosen by the RTE, the power transmission management. Between October 1998 and February 1999, 800 PRISMETER 2 meters were installed on the transmission network. Their high metrological accuracy and features perfectlymeet established terms and conditions.



There are many industrial processes involvingtemperature: heating, firing, heat treatment,

fusion.The measurement systems implemented to testand regulate temperature form a complete systemknown as a thermal process loop.The temperature sensor is the sensitive part ofthis loop.

Exposed to harsh and repeated stresses, thetemperature sensor must be accurately tailoredto its application so to fulfil its function on a long-term basis. Obviously, this means that the tempera-ture range to be resisted by the process and theprocess setpoint temperature is known, yet alsodepends on conditions specific to the process inquestion: chemical nature of the environment to bemeasured with its physical and mechanicaldemands.

Pyro-Contrôle Chauvin Arnoux, an expert in the production of industrial sensors, describeshere the technological choices that contribute tothe robustness and long life of a sensor.

RobustnessIt is essential for a sensor to be robust. Theprocess calls for much thought because there aremany aspects involved.What is the desired minimum life span of the sensor? In terms of time, what is the cost ofreplacing a sensor? If the sensor’s protectivesheath is doubled, how much gain can be gene-rated in terms of the equipment utilization factor?All these parameters have to be taken into con-sideration when determining the type of protec-tion and its life duration.

Naturally, the operating temperature first governsthe choice of materials to be used in manufactu-ring a sensor protective sheath.Industrial processes also affect pyrometer assem-blies by abrasion, pressure, vibration or corrosion.The media can be reductive, oxidizing, acid, alkalior sulphurous.Pyrometer assemblies therefore have to incorpo-rate suitable materials like special steel, nickel-base alloys, sintered metals, composites, plastics,ceramics.

Good vibration resistance means taking thestrength of the materials and the frequencies ofthese vibrations into consideration.

All the materials used in sensor construction mustcomply with this double-sided demand. Anotherelement of robustness is resistance to thermalimpact, often causing breakage or rupture,especially for ceramics.

Protection materials Protective sheaths are designed to protect thesensitive part of the sensor from undesirableinfluences such as fluid pressure or flow speed,chemically or mechanically aggressive media orelectrical influences. Each case means using asuitable material, possibly reinforced by a specialcoating. Protection can be obtained by a sheathlined with another sheath to deal with several different parameters at the same time.

Metal sheathsMetals most often used are:- dressed cast iron, pure iron,- stainless steels up to 400°C,- refractory steels up to 1,300°C,- nickel-base alloys up to 1,350°C,- lined metal tubes,- special metals, especially precious metals.

Dressed cast iron and pure ironDressed cast iron is used in aluminum and non-ferrous metal foundries, for instance zinc.Increasingly, they are being replaced by compositeceramic sheaths (see below).

Stainless steel Stainless steel sheaths are essentially used forchemical installations. In addition to mechanicalstrength, the need for good chemical resistanceto corrosion is an incentive to choose a materialidentical or similar to that of the installation itselffor the protective sheaths. Welding capabilityshould also be checked.

There are special prescriptions for installationshandling food or pharmaceutical products. Wemight mention the more customary steels: AISI 304L, AISI 316L and 316 TI.

Refractory steelsThese are used essentially for sheaths placed inovens, fire boxes, salt baths. These sheaths aregenerally not exposed to solicitation caused bypressure or flow. They have to offer optimum resistance to high temperature oxidization. The more frequently used are: AISI 321 and AISI 446.

Pure nickel and high nickel content alloys- Nickel-chrome or Inconel alloysInconels have a high nickel and chrome content,endowing them with resistance to oxidizing andreducing media. They are suited to high tempera-ture corrective environments. Some alloys haveexceptional fatigue resistance.- Nickel-iron-chrome or Incoloy alloysThe presence of approximately 40% iron endowsIncoloys with properties of resisting carbiding. Theyoffer excellent resistance to high temperaturesand to sulfur attack and corrosion.- Nickel-copper or Monel alloysMonels have a high copper content of around 30%.These alloys offer high mechanical strength, goodwelding capability and excellent resistance to corrosion in a vast range of temperatures and fordifferent environmental conditions.- Nickel-chrome-Molybdenum/Iron alloys or Hastelloy

Hastelloys are particularly effective in corrective,oxidizing and reducing media. Their versatility andresistance to fatigue mean that they are oftenused for fine chemical processes. Some are usedfor household refuse incineration.

Coated metal tubesMetal sheaths coated with a material suited to

Protective sheaths for pyrometer assembliesAt the very heart of measurement, the temperature sensor is the sensitive element of a measurement process loop. Exposed to severe and repeated stresses, it must be robust and protected accordingly by a sheath to guarantee a minimum life duration.

Depending on the expected type of protection,protective sheaths can be built of many

materials: refractory steel, stainless steel, alumina, ceramics


cope with the environment, offering good chemicalresistance in addition to mechanical strengthoffered by the supporting tube (Fig. 1).

Special metalsFor cases where nickel-base steel and alloy isinsufficient, special metal protection sheaths areused (Fig. 2).

Non-metallic sheaths Plastic sheathsPlastics most often used are PTFE, polyamide andPVC (Fig. 3).

Sheaths of ceramics and other amorphous materials

Operate essentially at high temperature whenmetals can no longer be used or do not offer suffi-cient life duration. Alumina or aluminum silicateceramic sheaths are suitable for noble metalthermo-electric couples (Fig. 4).

These sheaths are particularly sensitive to thermalshock: excessively fast entry into the hot zone willcause a thermal dilatation gradient that can breakthe sheath. On contact with dust at high tempera-ture, vitrified deposits often form on their surfacehaving a different thermal dilatation factor: exces-sively fast withdrawal could cause the sheath toshatter. Gas-tight sheaths are more sensitive tothermal shock.


Coating Properties Examples of use

PTFE Resists weak acids and alkalis. Chemical installations without

Mediocre heat conductivity. longevity demands.

Stellite Very hard, resists high Rotary furnaces, air containing

temperature abrasion. abrasive powder.

Coating deposited by welding.

Mild Good resistance up to 450°C Zinc bath.

enameled but fragile on impact.

steel

Material Properties Examples of use

Platinum Resists oxidization even at Manufacturing of

and high temperature. hydrofluoric acid.

platinum- Resists acids and alkalis. Glass and enamel baths.

rhodium

Tantalum Excellent resistance to acids Tantalum-coated pipes and

and alkalis up to 300°C boiler-making: for nitric acid;

(exceptionally, 400°C). lactic acid, bromide, iodine.

Silver Resists oxidization up to Silver-coated chemical

400°C. Resists acid partially, installations.

e.g. phosphoric acid.

Molybdenum Resists temperature- Atmospheric ovens with the

reducing atmospheres. presence of hydrogen.

Kanthal Presence of protective Gas ovens.

alumina coat offering

properties of resistance

to oxidizing and sulfur-

bearing media.

Coated metal tubes (Fig. 1)Examples of coated metal tube applications

Coating Properties Examples of use

PTFE and Resists weak acids and Electro-plating and acid baths.

polyamides alkalis.

Mediocre heat conductivity.

PVC Low resistance, maximum Applications without

strength 100°C - Coating any particular requirements.

deposited by welding.

Plastic material sheaths (Fig. 3)Examples of applications with plastic material sheaths

Special metals (Fig. 2)Examples of applications with precious metal sheaths

Cannes CADID for high temperatures starting from 500°C.

The sensitive element: a pearl-type thermo-couple covered with metallic protection or

a sheath of ceramic or alumina.


Conversely, coarse-grain sheaths offer better resis-tance but have high porosity.

Composite material sheaths (Fig. 5)

Mechanical properties Mechanical strength The mechanical strength of steel decreases withtemperature. In addition, corrosion and abrasionhelp decrease the effective sheath thickness. Thisshould be taken into consideration during calcu-lations. Ceramic sheaths also lose their strengthat high temperature. Up to a given temperature, thestrength characteristics vary relatively little, butbeyond tend to become very quickly and emphati-cally depleted. This limits the range of use of cera-mics to below this temperature setpoint (indicated by the suppliers).

Resistance to corrosion and abrasionFrom the standpoint of chemical strength, thechoice of a suitable material for the sheath callsfor great attention. In aqueous solutions, an elec-tric battery effect occurs (for instance, betweenthe sheath and the boiler walls), always aggrava-ting corrosion when the distance between the tworeactive materials is small.

This gives us the following basic rule: the sheathmust be manufactured from the same material asthe equipment or from a more noble material fromthe electric standpoint.It is possible to obtain data from steel manufac-

turers about the loss of weight (per cubic meterand year) and the resistance of refractory steel tooxidization. These values apply to calm air. Theresistance to oxidization of chrome-nickel alloyscomes from the adhering oxide coat which limitsoxygen penetration. When this oxide coat isdamaged, for instance if dust particles or sandare carried by the air flow, the damage will increasesubstantially. There is no way of setting valid values as a general measure. To improve abrasion

resistance, suitable coatings are used on metal sheaths: stellite and shooping are typicalexamples, as are vacuum plasma processes. The latter allow a wide variety of coating materialsto be used on a range of different substrates.




Graphite Electricity conductor; can be Aluminium foundry.

used to 1,800°C; mandatory

to use insulating internal

sheath such as alumina 710.

Nitride High mechanical strengh, good Foundry work for aluminium,

binder resistance to thermal impact - zamac, zinc and copper

Silicone Resists oxidizing and metals. Incineration furnaces.

carbide reducing atmospheres -

Max. Temperature 1,600°C.

Silicone Excellent corrosion Zinc bath.

nitride resistance for non-ferrous

metals. Max temperature

1,250°C.

Sheaths and composite materials (Fig. 5)Examples of applications with sheaths of composite materials


Ceramic Resists up to 1,500°C; Material most often used

530 not very sensitive to thermal in metallurgy and heat

shock; porous. treatment ovens, often

used as double jacket.

Alumina Resists up to 1,800°C; More current materials

710 very sensitive to thermal in metallurgy and heat

shock; low porosity. treatment ovens, at high

temperature than

ceramic 530.

Quartz Resists acids (except HF) Steel bath up to 1,600°C.

and alkalis - Insensitive Semi-conductor ovens.

to thermal shock.

Sheaths of ceramics and other amorphous materials (Fig. 4)Examples of application with ceramic material sheaths.

Quartz sheaths resisting acids and alkalis are used in the chemical world.

They are insensitive to thermal impact and can be used to very high temperatures.

They are also used in metallurgy.They guarantee purity compliance in semi-

conductor manufacturing


A P P L I C A T I O N

Heat treatment process control, especially theforging of materials used in the composition of

aircraft engines, ensures quality and safety of thematerial and of the people being transported.That is why SNECMA, over the years, has develop-ed the concept of a manufacturing “instructions”specifying the ways of testing parts used in thecomposition of aircraft, and establishing referencesfor the measurement instruments used for testingthem.

Accuracy and consistency for a furnace holdingtemperature are two primordial elements gover-ning quality and cost of the resulting heat treat-ment.

Why quality?Because the mechanical characteristics obtainedduring tempering, for instance, depend on thetemperature reached during heating at every pointof the load, and any fault in accuracy and consis-tency will lead to variations in the propertiesobtained, and therefore dispersed quality.

Why the cost?Because any reduction in temperature deviationsbetween two points in a furnace enclosure willresult in a decreased heating setpoint, and there-fore, by stopping the superheating process, providean energy saving.At 1,000°C, saving a single degree makes forconsiderable economy.In the long term, limiting the amount of overheatingwill also extend the equipment life duration.

Furnace mappingFurnace mapping is an essential part of heat treat-ment process control. Furnace and oven suppliers know how to meetspecifications that stipulate the equipment“class”.The class of a furnace is the maximum differencebetween any two points in the enclosure. Thismeans that a class 10 furnace is not supposed to

generate more than 10°C deviation between allthe points of the load.This is only in theory. In practice, furnace mapping,with or without a load, is a way of checking.

Reception of a new furnaceTwo types of mapping can be applied for certifyinga furnace, checking compliance with the originalspecifications. The characteristics found will beused for writing up the acceptance report.The acceptance report will be used for writing theprocedure applicable to future mapping and deter-mining the periodicity needed between two main-tenance mapping processes.

These two types of mapping are:- No-load reception mapping: empty furnace (seephoto)

- Reception mapping with a load: furnace contain-ing a correct amount of material.

Furnace maintenance A new furnace mapping process is triggered on adue date, or by observing an anomaly on with-drawal from the furnace.Effectively, at SNECMA, each part is measuredthermally by a production agent using portableapparatus. If the measured temperature isabnormal, the fault is reported to Mr. FERBOEUF’sDepartment, who will seek the defective compo-sition in the furnace.After repair, another mapping process is always run.

Temperature measurement and recording The furnace to be tested is “instrumented”.With temperature sensors that are connected to ameasurement unit.

No-load consistency testingTemperature consistency tests are carried out atfour different setpoint temperatures. The tempera-ture values are chosen according to the furnaceand the parts that will be treated in them.

- The process begins at ambient temperature withstabilization at a first temperature level.Stabilization may last several hours. The furnaceis destabilized (e.g.: doors opened) for 30 minutes and another stabilization level isallowed for 30 minutes.

- Then, another increase to a second temperaturelevel is requested. There is a one-hour stabiliza-tion waiting period, then the acquisition systemrecords the values obtained by the temperaturesensors for one hour. This is followed by 30 minutes’ destabilization, followed by furthersstabilization for 30 minutes.

- Then the temperature is increased to the thirdlevel with the same cycle as before, and thetemperatures are recorded for one hour.

- The fourth cycle is a reduction in temperaturewith return to the initial temperature value.

- The last temperature cycle consists in bringingthe system back to max. temperature again andmeasuring the temperatures.

On-load consistency testThe test is run at two different temperatures accord-ing to a preset cycle and, for each temperature,the load tonnage will be modified.

Furnace mappingat SnecmaWe met with Mr. FERBOEUF, in charge of the Snecma forge workshop, who gave us a particularly warm welcome and told us about his work: furnace metrology.“Furnace mapping implies mastery over global quality and applies to the heat treatment of metal parts f/or aircraft engines.”

A look at the Snecmagroup

Among the very biggest worldwideengine manufacturers, Snecma isalone in mastering such a completerange of propulsion technologiesfor civil and military and transportaircraft, helicopters, missiles, dro-nes, satellites and space launchvehicles with a thrust range exten-ding from 8 grams to more than650 tons.

This forge furnace is “instrumented” for no-load mapping (empty furnace). All 27 temperature sensors are set out through

the volume of the furnace (3.67 x 3.55 x 2 m) and connected to a measurement unit. No-load temperature consistency tests are run

for four different temperatures (maximum 1,200°C). On completion ofthese tests, the furnace will be declared as conforming or not.

Pho

to S

NE

CM

A


TEMPERATURE SENSORS:The temperature sensors most often used inmapping applications are K type thermocoupleslined with Inconel (resisting up to 1,150°C).

All our K thermocouples lined with Inconel are inclass 1(1). The extension cable is usually PVC insu-lated after binding with a shield braid and PVCsheath; other types of sheath are available onrequest, glass silk insulation, silicone sheathing orFEP.

(1) According to standard NF EN 61-515. (2) According tostandard NFC 42-330.

DATA RECORDING AND ANALYSIS ON THE PC

This PC digital temperature recorder consists ofthe “Pyrotracer” software and digital transmittermodules of the C.A 3100 general-purpose inputtype. Between 1 and 32 modules can beconnected, depending on the application.

These modules have an RS 485/Modbus protocoldigital output.

Each channel has a low and a high alarm.There are two available recording modes: batchmode or programmed starting and stopping in timeand the “continuous” mode with constant datarecording.


Our tailor-made solutions Pyro-Contrôle Chauvin Arnoux converts every measurement and test requirement concerning temperatureinto an industrial solution. In this particular application of “furnace mapping”, it is competent to offer the fullchain: sensors for measurement and the PYROTRACER modular system for recording and restoring data.

Pyrotracer:1 to 32 measurement channels.Easy data analysis directly on the PC.

TCG3 sensor: K type thermocouple lined withInconel, PVC extension cable output.

A P P L I C A T I O N

“Consistency test” reportAt SNECMA, the following information is recordedfor each furnace: Name, volume characteristics,maximum load, temperature range, temperatureclass, name of the temperature recording equip-ment and metrological validity, a table of measure-ments*, general observations, quality decision. * All the temperatures from the thermocouples are entered

into a table.

Other important information is also recorded, suchas: regulation time, stabilization time, overruntime, stabilization max. and min. temperature,perturbation max. and min. temperature, stabiliza-tion minimum amplitude, rise time.

On completion of all these measurements, thefurnace will be declared good or bad by the qualitydepartment.


3670

18-25

200485

650

650

650

650

920

355

16-23

13-20-2711-15-22

10-14-21 12-19-26

17-24

6

5

9550

3

2

1

8

74

Location of temperature sensors in furnace.The temperature setpoint is obtained by gas heating diffused by burners.

The thermocouplesensors are set out asfollows:

- numbers 1 to 9 are placed on the base

- numbers 10 to 13 are placed on jacks at a height of 0.5 m

- numbers 14 to 20 are placed on jacks at a height of 0.7 m

- numbers 21 to 27 are placed on jacks at a height of 1 m.


Chauvin Arnoux

Test & Measurement The complete and up-to-date productoffer. Within the 32 illustrated pages of this 2002 catalogue, the Test &Measurement division presents metro-logy professionals with its full range ofChauvin Arnoux brand hand-held, field,and laboratory instruments: Electricaltesting and safety, Current measurement,Hand-held testers, Energy analysis, yetalso LAN and telecommunications testingand Microwaves.

23

K I O S K

Multi-purpose voltage

absence tester

Equipped with a modular casing comprisedof interchangeable adapters and thin,full-safety test probes, the C.A 700 is asto-nishing in its ability to adapt to any type ofelectric cabinet and safety socket, acces-sing even hard-to-reach spaces. With features including voltage detection,phase/neutral and continuity, the C.A 700perfectly meets the European IEC 61243-3 standards. Discover its multiple applica-tions in the sales literature.

Analogue oscilloscope

This 2-sided brochure presents ourcomplete, reliable and uncompromisingSINGLE-CHANNEL OSCILLOSCOPE: the X4010. The well-known fact that it is veryeasy to use should not be allowed toeclipse its features: 10MHz bandwidthover the whole sensitivity range, 10 inputranges between 5 mV and 5 Volts per division, triggereing up to 30 MHz and indication by “TRIG” LED, XY mode at 1 MHz. Discover its other features in thiscomplete document.

Two essential guides for a time marked by the

deregulation and privatization of the energy

market!

The “Product” guide presents the C.A Enerdis offer for requirements in measurement,metering, display and monitoring of electrical networks. This offer is structured aroundthe POWER and NODUS power monitors, CDT remote-operated electronic meters, CCTpulse receivers, and WinThor energy management and monitoring software. To comple-ment this guide, the “Solutions” guide re-examines your electrical installation’s monitoringneeds. It explains in detail the principle of an energy management system, the advanta-ges of remote-reading indices, and the result analysis for taking corrective action.Reader Service No. 21

Power

Measurement & Control

Within this 2002-2003 catalogue (126pages), the Power Measurement & Controldivision presents its entire product offer soldunder the CA Enerdis brand name, an offerintended for utilities and electricity compa-nies, installers, switchboard operators, manu-facturers, industrial firms, and engineeringfirms and public administration. This cata-logue is particularly enriched by the ULYSelectronic energy meter range designed forall sub-metering applications, the new NODUS D power monitors, and digitaldisplacement measurement systems and meteorological measurement.

Temperature

Measurement &

Control

This 2002 catalogue presents the Pyro-Contrôle Chauvin Arnoux “standardproduct” offer. It includes a choice ofsensors and temperature measurementand control systems, available at whole-salers - distributors specialized in “indus-trial process.”

Metrix

Test & Measurement Within its habitual 32 color pages, Metrixpresents its product range within selec-tion tables. Set forth in a very clear way,comparisons between equipment aremade using each's specifications. Photosof each of the multimeters, oscilloscopes,generators, power supplies, accessories,and other instruments are included tomake the selection more simple.



Reader Service No. 22 Reader Service No. 23



The best in electrical equipment

Power Measurement& Control Division of

1-9 rue d'Arcueil - BP 67592542 Montrouge Cedex - France

Tel.: + 33 1 47 46 78 85 - Fax: + 33 1 47 35 01 33e-mail: [email protected]

www.enerdis.fr

EnergyEnergy to save ?

The new range of ULYSmeters provide a simple,

rapid and economic solutionto all of your electrical energymetering requirements on LVand MV networks.Designed for industrial andservices sector sites, thiscomplete range of 6 meters

has numerous assets:

For single-phase and three-phase networks, 60 mAto 90 A direct inputs or connection to 1 A and5 A current transformers, 57.7 V to 400 V

Display and configuration possible when the ins-trument is disconnected

Single or dual-tariff active and reactive energymetering

Measures the instantaneous and maximum power

Zero-resettable metering for periodic energymanagement

Programmable current/voltage ratios and pulsetransmitters

A new range ofenergy metersA new range ofenergy meters

Total IEC

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No.

24

no. 17 measurement • news 2002 · for further information, contact your local agency, or our...

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